Safety-fuse.



L. KOVACS.

SAFETY FUSE. APPLICATION FILED OC'I. 30,1911.. l

Patented Jan. 7, 1913.

2 SHEETS-SHEET 1.

L. KOVAGS.

SAFETY FUSE.

APYLIGATION FILED OUT.

2 SHEETSASHHF 2.

ateuted San. T,

i UNITE- semaine rarer@ foreros.

LOUIS KQVACS, OFCHICAGO, ILLINGIS.

SAFETY-FUSE.

Specification of Letters Patent.

Applieatlonled October 30, 1911.

lPatented Jan.. 7, v1913. sensi No. 657,498.

To all whom it may concern:

Be it known that I, Louis Kovacs, a subject of the Emperor 'of Austria-Hungary, and residing at Chicago, in the county of |Cook andv State of Illinois, have invented a new and useful Improvement in Safety- Fuses, of- Whicli the following is a complete specification.

The main objects of, this invention are to provide an improved safety fuse for electric currents;

adapted to be used for a given current strength and Which is so constructed as to' render it impossible to send a higher current strength through it than that for Which it is rated; toV provide a safety fuse adapted for use with a Wire of certain and so constructed that the parts of a safety fuse designed for a higher current rating cannot be'connected with its parte; and 'to provide a safety fuse adapted to be economical in its operation.

In' thedrawings: Figure l is a central longitudinal section of a safety fuse embodied in this invention. Fig. 2 is a longitudinal sect-ion of the safety fuse taken at right angles to the section shown in Fig. 1. Fig. 3 is a side elevation 'of the safety fuse -with the safety plug detached from the safety block. Fig. 4 is a modified form of the safety fuse. Fig. 5 is a top plan View of'the safety plug. Fig. 6 is a central, longitudinal section of the plug. Fig. 7 is a bottom plan View of the' plug. Fig. 8 is a plan vieW of the binding plate for the safety plug contact. Fig. 9 is a side elevation of the safety plug contact With its binding plate in section. Fig. 10 is a central longitudinal section of the insulating body for the safety plug. Fig. 11 is a longitudinal section of the insulating body taken at right angles to the view shown in Fig. 10. Fig. 12 isa centralsection of the Contact support for the safety block Contact. Fig. 13 is a bottom plan View of the same. Fig. 14

is a longitudinal section of a light plug adapted for use with the safety block. Fig. 15 is a view-similar to- Fig. 14E-butA taken at right angles thereto. l

Referring first to Figs. 1 and 2, the safety block has a base l which is preferably constructed of marble or slate and has .a cavity or recess 2 in its upper face in which; is mounted the safety block contact support comprising a lower cup 3 which lits closely inthe Arecess 2 and an uppercup 4 Whichis fthe base platev 1 is .to provide a `safety fuse The safety block contact I0, of copcurrent rating inverted in the lower cup. Said cups are preferably formed of brass or copper and the upper cupis provided with slots 5 .in its sides into which projectguide screws 6 and .7 carried in the Walls of the cup .3. A coiled spring 8 is carried in saidl cups and is adapted to normally'hold the cup 4 at the upper limit of its movement.- Covering said recess 2 and countersunk inthe top of a plate 9 of ebonite or fiber. per, extends through the plate 9 and proyects above the same. Said contact is pro- 'vided with a reduced portion 11 which ex- .tends through an aperture 12 in the top of `the cup 4 and the shoulder formed by said .reduced portion rests on the top of the cup 4. 'The reduced portion 11 is provided With ,screw threads on which' are engaged binding nuts 13 lWhich bear against the inner `side of the cup 4 and hold the contact Afirmly in place. The extreme lower end 14 `of the cont-act. projects into an aperture 15 in the bottom of the cup 3 which acts to yguide and brace the contact in its vertical movement. Secured on the top of the base 1 by means of screws 16 is an out r shell 17 of fiber Within which and fitting closely thereto is an inner copper shell or socket 18 which is provided at its bottom With an in: ternal ange 19 which rests on the top of the base 1 and overlaps the edges of the plate' 9. The-safety plug 20 is adapted to tit within the socket thus formed and comprises a central insulating body 21 of porcelain TWhich has an axial bore 22 therethrough. A brass or copper sleeve 23 incloses the body 21 and is provided rvith'an inturned flange 24 which overlaps the hottom of the hotly 21 and screws 25 extend through said ange and project into cavities 26 in the sides of the body 1n 'which are nuts 27- to which said screws are scoured. The flange 24 and the flange 19 extend inwardly the same distance and aprojection 28 on the bottom of the body 21s projects into the aperture in the flange 24 and rests on a like projectioifon theplate 9 which extends into the aperture in the flange 19.

The upper end A3f-,the body-21 has an angular portion 2 9. on .which is seated'a fas- Lening plate 30 whichl is secured -to the'body 21 by means of screws 31 which extend through the plate and into the cavities 32'- in the bod 21 and engage nuts 33 in the cavities. f

cap ..34 of porcelain seats over the plate and the upper end of the body 21 and rests on the tops of the sleeves 17, 18, and 23, and is secured to the plate 30 by means of screws passing through apertures in the cap and into'the plate'. The cap has a recess 36 in its outer side in which the plate 30 is carried, and which opens upwardly through the top of the cap through an aperture 37. The safety plug contact 38 is secured to the plate 30 by means of nuts 39 and projects into the bore 22 of the body 21. The-body 21 has a `passage 40 which' extends upwardly from one of the cavities 26 and opens into the recess 36 in the cap, and a fuse 41 of a is carried in the passage and is connected at one end to the screw 25 and'at its other to the upper end of the cont-act 38 by means of the nuts 39. The passage 40 and the recess 36 are then filled withasbestos filling 42, and the recess is closed by a. layer of mica 43. Secured to one side of the sleeve 1 8 and to the base 1 is a brass binding platescrew 7 and extends laterally from the top of the cup in a recess in the base 1. The recess above the lateral ortion of the conductor is filled with asuitable filling, and a binding plate 47 is secured over the filling by means of a bolt 48. A binding screw 49 is carried in the plate 47. For" tl'e purpose of securing the safety plug to the safety block'the sleeves 17 and 18 are provided with a curved notch 50 in which a screw 51 carried on the plug engages when the plug is in place.

1n the construction shown in Fig. 4 the safety block 1 opens at its bottom for the insertion and removal of the contact supporting caps 3 and 4, and the opening is then sealed with a filling 52.

In Figs. 14 and 15 are illustrated a lampl plug 53, in which the cap 54 has a socket 55 to' receive alamp bulb 56. The negative terminal of the lamp is provided by a bolt 57 extending from the lamp socket through the body 21 and {iange 24-of the sleeve 23. The positive terminal is provided by a contact 58 which is carried in a plate 59 of ebonite or fiber.

The current enters at the binding post 45 and lthence passes, successively, through plate 44, shell 18, flange 19, screwI 25, and fuse 41,' from which it is adapted to enter the lamp at the positive pole. Leaving the lamp at the negative pole, the current passes, successively, through safety plug Contact 38, safety block contact 10, cup 4', cup 3, screw 7, plate 46, and binding post 49,

vit being understood that the negative line wire is -connected to post- 49. This path of the current can be most clearly traced in Fig. 2 of' the drawings. The current must 'ven currentstrength necessarily pass from .plug 38 to plug 10, which are both made of copper and4 which are held in frictional contact with each otherby -the action of the helical spring,

which is found within the telescoping cupsl 3 and 4. If said plugs 38 and 10 do not touch, there will be a breakin the circuit and the current will not bridge the gap, and it is the essential object of this invention so to construct said yplugs and associatedparts that the plugs will be in electrical connection only when plugs" of the proper size are being used.

As is well known in the art, for every size and grade of wire there is a maximum amperage which that wire can carry, and fuses which are adapted to melt when the amperage reaches or exceeds the maximum, are placed in thecircuit in order that the circuit may be broken before the wire itself beeomes too hot. ln many instances, however,

employees who install or maintain electrical apparatus, for various reasons frequently use safety plugs which will not break the circuit at the same amperage as the fuse which is being used, and this often results in causing fires or accidents to the main wire or the electricalapparatus because the safety devices .do not blow out at the proper time.

It isithe essential object of this invention to provide a construction in which the plugs for a given amperage cannot be connected with a block designed for a different amperage and thus make it impossible to combine together a safety plug and a block which are not mated for each other. It being obvious from what lias been stated above that the current must pass through plugs 38 and 10, it follows that anything which prevents a proper connection between said plugs will make a break in the circuit between posts 45 and 49. In order thatthis connection may be maintained when shell 23 is placed within the socket 18, the sum of the lengths .of plugs 38 and 10 must be exactly enough to span the distance between the members'30 and 4. If, forexample, the plug 10 be too short, the circuit will be incomplete because the current cannot bridge the gap between plugs 10 and 38; but, on the other hand, if the plug 10 be too long, it will prevent assembling the device and will not permit the cartridge containing the fuse to be seated within the shell secured to the base 1. The

plugs 38 and 10, tlnucfore, are made of certo the mark 2, Fig. 9, and in such case, the

plug 10 will be relatively short. If the wire the plug correspondingly increased.

drical in shape.

#of any particular size,

rating be' 60 amper-es', the plug' 38 will eX- tend from the member 30 only to the line 6, Fig. 9, and the length ofthe plug lll-will be For a current of say 300 amperes,.the plug 38 will be very short,.extending only to line 30, Fig. 9, and l() will be very long. The plugs are not designed to blew out or melt since they are made heavy or thick enough to carry practically any current, but they either prevent assembling the shell 23 within the shell 18 or cause a break in the circuit unless therespective plugs carried upon the cartridge and upontlie base are each of the right length to complete the circuit. The carelessness of employees is thus guarded against, because the respective plugs 38 and l() are placed within t-he cartridge or fuse plug and the rrbase at the factory and cannot vreadilyV be removed. or inserted at the job, and the workman who is instructed to ar-A range 'the circuit for any maximum amperage, absolutely must use a cartridge and a ase containing the plugs of the length designed to meet and touch each other for that amperage. lf the workman does not so do, the electrical connection will not be established.

.The members l'0`and 38 have herein been.

referred to as plugs and in the drawings they are shown as being; substantially cylin- It should be understood, however, that the the claims, is not to. be limited to a conductor shape, or material but that the essential feature of the ini/'ention consists in providing the cartridge aflid the base with co-acting parts which will establish electrical connection only when the part or plugon one member is of the right length to engage the part or plug on the other,after the cartridge and base have been higher designed to carry, the safety Jfuse il will blow outhbreaking the circuit and making it necessary torein-ove' the cartridge or mein ber within which .the fuse 41 and the plug i. 38 are carried and to substitute another vIto which must be obtained from the factory.

" Each cartridge, of course, will contain both which is proportionate to '55 a fuse 4l adapted to blow out at a-'given amper'age, and a plug 38, the length of the amperage at which the fuse will blowout. Since the f plugs will be .inserted at the factory where the .workmenare less likely to make a mi'stake 'and under practically no temptation deliberately tol err, the cartridges as they leave the factory will be, equipped with plugis 38 of' the proper length, cpnsidering .the rated amperage of the Wire in connec-4 tion 'with which any particular cartridge.

andbase is te be used. The workman on the. job, therefore, who is installing orreto accordwith lmerely to save himseltl inconvenience and extra labor or delay, substitute a cartridge or a base adapted-for a wire of a diil'erent rating.

i conducting term plugas used in.

wire 1s lpairing must use a cartridge and a base,

each of which has a plug of the proper size the wire ratings and cannot,

I claim as my invention: lqln a clerics or the character described,

' the combination of a base, a cartridge adaptjed to be secured thereto and comprising an insulating member, said base and said block fbeing provided with registering recesses,YJ a

lug ixed in one .of said mehr fbe'rs and a apted to engage a conducting plugretained resilient means to lreep said plugs in engageff, ment, and a fuse, the length of each of saidl plugs being proportional 'to the amperage at which said fuse is adaptedto blow out. 2. ln' a device or" the character described,

in the other of said members,

the combination of a base, a pair of telescoping cups therein, resilient means interposed between said cups, a cartridge adapted to be secured to said base, said base and said cartridge being provided with registering recesses,iand co-'acting conductors retained within said recesses, one of said' conductors being connected Ito and movable with one ovsaidtelescoping cups. i'

l 3. ln a device of the character described, the combination ost-a base, an insulator bloei: adapted and said base being provided with registering recesses, abuttingplugs ,retained in said recesses, one of said plugs being Xedft-o its support, the other of said able, and a yielding. means engaging said movable plug and adapted to` force same into contact with' said iiXed plug, the length of each of said plugs being proportionate to theamperage in connection with which the device is intended to be used.

ll. ln a` devicemf'the character described, the combination of a base, a pair of telescoping cups therein, resilient means interposed between said cups, an insulating member above said cups, saidl insulating member being, perforated, a conducting member ass ing through said peroraticn and Using movable therewitliin, 'sa-id conducting niemnber being secured to one ci aaidcuns, a cartridge adapted to be secured to said base. said base and said cartridge being provided with registering recesses, ductgrs within said recesses.

5. 'in a device of the character s? lcrbegl, the combination of a. base, a cartridge adapted to be secured thereto, said-base and saidcartridge being rovidedl with registering recesses, an insu ator ada' 'ted to seal one;

f said' recesses, said insu eter being ler- -ih irated, abutting plugs retained insai re plugs being adapted to casses,l one of said pass through the perforation in said insular to bey secured thereto, said block plugs being niovand 3o-acting.'ceneY 120 .ietf

tor, the other of said plugs being fixed, and resilient means Within the recessl which is sealed by said insulator, said resilient means being adapted to force the plug passing through said insulator into contact With the other of said plugs, the length of each of said plugs being proportionate to the amperage in connection with which the device is intended to be used.V

6. In a device of the character described,-

the combination of a base, a cartridge adapt ed to be secured thereto, an insulator interposed between said base and said cart-ridge, a pair of contacting plugs retained by said base and said cartridge, one of said plugs being movable and the other being ixed, resilient means, and means projecting through said insulator adapted to' receive' the force of said resilient means and keep said mov- Copies of this patent may be obtained for five cents each, by addressi.

able and saidA fixed plugs gagement with each other.

7. In a device of the character described, the combination of a base, an insulating member adapted to be secured thereto, a

pressed into encartridge also secured to said base, a pair Witnesses.

LOUIS KOVACS. Witnesses:

JosiahA SICHLENKER, v Ro'r. vLorz.

Washington, D. C.

the Commissioner of Patents, Y 

